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Your best bet , take it to a qualified repair shop . You have know idea how complex the electronics are on your vehicle are . So before you short something out an make thing's worse . If it shuts off after 4 seconds it's a anti-theft problem . Take an have full vehicle scan done , Knowing how the start system works is the way to a fix . Turning the key to start send a voltage input to the BCM ,the BCM sends a message over the GMLAN serial data network to the PCM / ECM - engine computer requesting start , the PCM / ECM will then energize the starter relay sending battery voltage to the S terminal on the starter solenoid . The PCM / ECM isn't receiving a message from the BCM telling it to enable the fuel injectors . anti-theft system code ok
Anti-theft system problem will disable fuel injectors after 5 seconds shutting the vehicle off. The plugs are wet because the PCM richens the air fuel mixture for cold start . Is the Security Indicator flashing or on steady ?
When learning the pre-release password, as well as the challenge and response sequence, the engine control module (ECM) is placed in learn mode. DTC P0633 will set automatically as an indicator that the system is in learn mode and not as a fault indicator. Once the password and challenge/response are learned, learn mode will be exited when the engine is successfully started. At this point, the DTC will be cleared. If the ECM does not exit learn mode, P0633 will remain current and indicate a fault.
The "key" referenced in the DTC descriptor does not refer to the vehicle key. In this case, "key" is referring to the challenge response.
DTC P0633 requires a successful engine start to exit the learn procedure and clear the DTC. If an unrelated malfunction exists that causes engine starting to be disabled or otherwise unavailable, learn mode will not exit and DTC P0633 will remain current. In this situation, the cause of the inoperative engine starting must be corrected before diagnosing DTC P0633. DTC P1629: Theft Deterrent Fuel Enable Signal Not Received
The theft deterrent module (TDM) sends the pre-release password to the engine control module (ECM) via the serial data circuit. The ECM then sends a challenge to the TDM. Both the ECM and TDM perform a calculation on this challenge. If the calculated response from the TDM equals the calculation performed by the ECM, the ECM will allow vehicle starting.
DTC P1629 is an indicator that the challenge response was not received within the required 2 second window. This does not necessarily indicate a fault is present with the TDM or ECM. Factors such as a long engine crank, a delay in the serial data communication, or B-codes set in the TDM will cause DTC P1629 to set. This DTC should not be used as a fault indicator, but rather as a symptom to assist in the diagnosis of these other systems.
Who checked the codes , you -dealer ? You need to have BCM checked for codes B - codes ! you need a up scale diagnostic scan tool for that , dealer Tech -2 ! DTC B3935 57 : Transponder Authentication Error DTC B3976 46 : Unconfigured Transponder/Vehicle Configuration Not Programmed DTC B3060 : Unprogrammed Transponder Identification Code Received DTC B3055: No Transponder Modulation or No Transponder DTC B3031: Security System Controller In Learn Mode
You may want to do some research on the code. The basic problem is the anti-theft system is not seeing a crank signal and shutting down the fuel pump. It could be the security system, or the crank sensor, or other issues. If you have auto start or a remote starting system it can cause these problems too.
P1122 is a throttle position sensor code. P1629 is a theft deterrent system code. P1122 will set when the voltage signal from the throttle position sensor drops below 0.1 volts. Normally, the sensor should measure between 1 volt at idle and 4 volts at full throttle. A failed throttle position sensor could easily cause your problem.
As for the theft deterrent system code, with that code set, the car shouldn't start at all (if the code is active). With P1629, the engine computer should refuse to deliver fuel to the engine. This code can be stored for up to 40 warm up cycles before clearing itself, so unless it is currently active, there may not be any need to worry about it.
I would inspect the wiring and connectors leading to the throttle position sensor. If that wiring is good, I would replace the sensor and see where that got me. Give that a try and let us know how things go.
in the 1996 sunfire GM uses an anti theft lock system. It can be triggered by all sorts of things. In order to relinquish this you must have a key to turn the ignition. These are not coded just plain cut keys. Once you attain this you put the key in and turn the ignition to the ACC position and wait ten minutes (theft lock light will turn off), turn off and take key out. You MUST do this 3 times and then the theft lock will be disarmed.
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